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ZL3AI > APRDIG 19.05.04 09:21l 275 Lines 11042 Bytes #999 (0) @ WW
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Subj: TAPR Digest, May 04, 4/6
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: OT don't shoot the armchair lawyers... or should we? (was Re: Attn:
Armchair Lawyers)
From: "Keith - VE7GDH" <ve7gdh@rac.ca>
Date: Tue, 4 May 2004 11:14:09 -0700
X-Message-Number: 23
>...it all boils down to personal responsibility. Just like a gun dealer is
>not responsible if you buy a gun from him and murder everyone in the local
>(burger joint removed), Byonics/HiValue is not responsible to police the "10-4
good
>buddy"/"Don't give a damn" element of our service that won't take the time to
>learn the technical aspects of it.
Hope the irresponsible gun buyers don't target the armchair lawyers!
They would run out of ammunition.
I think the Pocket Tracker is a great product (haven't had time to build
mind yet) and used properly shouldn't have any negative impact on the
APRS network. As mentioned, those that beacon too often with too much
power or improper paths are the ones that harm the system.
I joined the APRS sig because some of the things I replied to on other
lists were deemed a bit "off topic." It was suggested that some topics
should move over to this list. Seems the signal to noise ratio is a bit low
here sometimes too. Not in any way referring to the quoted text above from
Jim (I agree with at least some of his comments), I think the "armchair
lawyer" thread is getting a bit ridiculous. I'm all for discussion of "deaf
trackers" vs "not deaf trackers" (even if they are sometimes running too
much power) and doing anything we can to make APRS work better, but it
would be nice to keep the discussion on the technical aspects and operating
procedures instead of about "rules" written by bureaucrats to cover
situations that didn't exist when they written last century. The best
"rules" are those that result from discussions amongst amateurs and not
from a government agency. I'm not saying that rules made by the FCC in the
US or Industry Canada (it's only a rumour that they are sometimes called
Idiots Canada) should not be followed, but we would all be a bit better off
if amateurs had more input into "rule making".
See... I said that it was off topic!
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am."
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Subject: Re: KG6BCP tracker on a Catamaran
From: "Keith - VE7GDH" <ve7gdh@rac.ca>
Date: Tue, 4 May 2004 12:50:55 -0700
X-Message-Number: 24
AH6LS said
>Neat idea (kites pulling catamarans)... not that a tracker on a sailboat
>isn't neat as well...
Just curious...on a catamaran, do you mount the GPS and radio antennas
on the top or bottom of the hull?
;-)
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am."
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Subject: Garmin 38 Voltage?
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Tue, 04 May 2004 15:56:56 -0400
X-Message-Number: 25
Has anyone used a simple resistor to reduce the voltage to a Garmin 38 from
the 14v automobile to the 6 volt input? In otherwords is the 5-8 volt
input requirement due to power dissipation concerns or instantaneous
voltage?
At 150 mA, looks like a 60 ohm 2W resistor would do it if the instantaneous
voltage transient is not a problem..
Bob
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Subject: OT? Garmin E-Trex setting
From: "Alton \(XP machine\)" <n5psp@n5psp.org>
Date: Tue, 4 May 2004 14:57:07 -0500
X-Message-Number: 26
Since my GPS-25 died due to "Pepsi Syndrome" a few months ago, I have been
using an E-Trex Legend as a tracker.
With vibration going down the road, sometimes the unit "thinks" external
power has been lost and "conveniently" powers itself down if no human
happens to see the warning screen in 30 seconds or so.
If the GPS is being used to track something unattended for a few hours, this
"helpful" feature is most undesired and unwanted.
Has anyone discovered some way to disable this most unhelpful and annoying
"feature" of the E-Trex family?
Desired behavior - if external power is lost (or intermittent), keep the GPS
powered on and feeding data to the TinyTrak until the batteries run down and
die. Batteries are cheap.
If external power is restored 20 minutes later, it should just run off
external power until it vibrates loose again, and then stay running until
someone notices and shoves the lighter plug the rest of the way into the
socket or the batteries finally die.
Yeah, eventually I'll finish wiring up the Deluo but the E-Trex Legend is a
stopgap until then.
Sign me "tired of re-booting the E-trex after every bump in the road".
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Subject: Re: OT? Garmin E-Trex setting
From: "J. Lance Cotton" <joe@lightningflash.net>
Date: Tue, 04 May 2004 15:08:04 -0500
X-Message-Number: 27
Here's my "not an answer to your question, but a related story is good
enough" response:
I had this problem, too. I just cracked open the etrex and soldered some
4-conductor flat-ribbon cable to the inside, ran it to the outside and
connected a 4-pin molex to it. Put the corresponding-gender molex on the end
of the cable and vibrations affect me no more.
Not a feasible solution for everyone... But how can you say you have fun in
life if you don't void a few warranties every week!
-Lance KJ5O
--
J. Lance Cotton, KJ5O
http://map.findu.com/kj5o-14
joe@lightningflash.net
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Subject: Re: Attn: Armchair Lawyers
From: Henk de Groot <henk.de.groot@hetnet.nl>
Date: Tue, 04 May 2004 22:25:36 +0200
X-Message-Number: 28
Hello Wes,
At 21:51 2-5-2004 -0400, wes@johnston.net wrote:
>Looks like we've got to switch to MACA or DAMA.... <grin> Anything else would
>have to be malicious interference. But, AX.25 was approved as CDMA which is
>really impossible on radio.
AX.25 is not CDMA (Code Division Multiple Access is a spread-spectrum
technology not related to narowband AFSK/FSK).
AX.25 is CSMA. AX.25 does sense for a carrier before transmission, so it is
truely CSMA as CSMA was meant to be. I know that with the high ammount of
hidden transmitters APRS is more like Aloha but that is the application.
You can build working a CSMA network using radio's, even with a better
performance than DAMA. DAMA is however needed because a CSMA network only
works well if all stations are properly tuned. In the HAM world that proved
to be impossible, so DAMA took the liberty away and created an unbalanced
master/slave network.
That being said I think I understand you confusion. I think you meant
CSMACD which is Carrier Sense Multiple Access with Collision Detect. That
means not only listening for a carrier before transmission but also listen
for interference during transmission (and back-off as soon as you notice
this...). I agree that is not possible. The most commonly known CSMACD
connection technology is Ethernet, aka IEEE 802.2 where multiple stations
share one physical medium. In a lot of cases they have become
point-to-point networks however to increase speed.
Kind regards,
Henk.
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Subject: Re: Kenwood d700a not reconizing my fixed station
From: "Keith - VE7GDH" <ve7gdh@rac.ca>
Date: Tue, 4 May 2004 13:28:22 -0700
X-Message-Number: 29
John KB3HIA asked May 03, 2004 4:22 PM
>Help! Does anyone know why my d700a will not reconize my (home) fixed
>station in its list of heard stations? I do see my fixed stations beacon
>text if monitoring packets (pmon). Several local hams have the same set-up
>as I, they recieve their home stations no problem. I am using the d700a
>mobile and I'm running UI-Veiw at the fixed station. My fixed station is
>using my call kb3hia, and the d700a mobile is kb3hia-9.If anyone can help
>please post or e-mail me direct at kb3hia@arrl.net. Thank You 73
Looking at www.findu.com/cgi-bin/find.cgi?kb3hia-9 , your raw packet is
as follows:
KB3HIA-9>S9TP5Y,KB3KUI,W3UD-3,WIDE2*,qAo,KA1UDX-1:'gAUl,Kk/]"3Y}
Ooops... It just moved! I'm looking at the wrong end. That's the beacon
with the compressed position from your D700 and not your home station
which is probably staying put.
Looking at www.findu.com/cgi-bin/find.cgi?kb3hia, the raw packet from
KB3HIA is as follows:
KB3HIA>APU16N,W3UD-3,WIDE3,N3IP,WC2AES-11,WA2JNF-15,TRACE3*,qAR,N2ZRC:=
3939.02N/07539.62W-Jay in Bear DE, kb3hia@arrl.net {UIV23N}
Hmmm... don't see anything wrong the actual position. As you mentioned,
you see the text when monitoring packets. Does anyone spot anything
unusual in there, or is it perhaps some setting in the D700?
I'm sure it's nothing to do with the actual problem, but you could
upgrade to UI-View32.
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am."
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Subject: Re: Power control, was yada yada
From: "Keith - VE7GDH" <ve7gdh@rac.ca>
Date: Tue, 4 May 2004 13:44:10 -0700
X-Message-Number: 30
Jeff said May 03, 2004 12:41 PM
>Thanks for reminding me of this. I had been comtiplating how best to do
>airplane tracking to best serve both collision avoidence as well as long
>distance location. More of a academic exercise, but interesting none-the-less
You would have to be pretty unlucky to be on a collision course with
another plane that also had a ham on board with APRS running. I would
worry more about the ones that didn't have APRS on board!
<snip>
>So, the thought I had was a tiered slotting system. One the minute do a 1 watt
>posit, on the 30 second mark, a 250 mw posit, on the 15 and 45, a 62mw posit,
>on the 7, 22, 37 and 52 a 15 mw posit, and then every other second in between,
a>2mw posit.
<snip>
Very interesting concept... as long as the other station was beaconing
often enough managed to transmit somewhere in between your "every other
second" 2 mW transmissions!
Just curious... when you have been air mobile with APRS running close to
a populated area, have you ever had occasion to see another air mobile
APRS station close enough to copy (that could take in quite a wide area
if you are both at altitude) and see how often you could decode the
beacon from the other plane when their signal was competing with
possibly a large number of ground stations that were transmitting? It
kind of comes down to the concept that the lower the ground trackers can
set their power (and still be heard by adjacent digis), the better the
whole system will work.
I had occasion to watch 3 planes flying around a few days ago. While
APRS in general is pretty neat, it was very interesting watching them
flying around, usually close to each other. I was assuming they were
planes going by their icon on the screen, but if they were ground based,
they should have been picked up for speeding!
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am."
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